Polybrominated diphenyl ethers (PBDEs) are common flame retardants used to reduce the risk of fire in a wide variety of products, such as mattresses, furniture, home electronics, textiles, upholstery fabrics, carpet, and children's toys. As a consequence, wide spread occurrence in the environment and bioaccumulation through various exposure routes have been revealed posing concerns to public health because of their potential adverse effects on human health. In this respect, there is a high demand to develop a field-portable rapid "on-site" detection method for early diagnosis of human exposure or environmental monitoring. In order to meet this need, Synthia-LLC proposes the development of a field-portable biosensor for BDE-47, one of the most toxic PBDE congeners. Using patented technology referred to as a phage anti-immunocomplex assay (PHAIA) which is a versatile non-competitive two site assay format for small compounds based on an analyte-antibody complex specific phage-borne peptide as the key technology, Synthia-LLC will develop a homogeneous fluorescent energy transfer PHAIA in a liquid core waveguide (FRET PHAIA-LCW) by setting three aims to achieve the goal. The first aim is the development of a standard 386-well plate based homogeneous FRET PHAIA by taking advantage of the poly binding nature of the phage particle. We expect that efficient fluorescent energy transfer through multiple interactions between an individual phage particle conjugated with the lanthanide donor in high density and many antibodies labeled with acceptor dye will not only enhance signal intensity, resulting in better sensitivity, but shorten general assay time because there is no need for repeated washing and incubation. The second aim is the establishment of a simple sample extraction method from biological samples. We expect that the simple extraction method will eliminate any matrix effect that may cause a false positive or negative result and thus enhance the detection accuracy of the assay. The third aim is a feasibility test of the FRET PHAIA-LCW in a simple device design. For Phase I, this test will be carried out using a commercially available liquid core waveguide cell. We expect that the property of the LCW in guiding the fluorescent signals to the detector with minimal signal loss will further enhance the assay sensitivity and the liquid phase assay can be easily extended to an automated compact type device. PUBLIC HEALTH RELEVANCE: The assay device proposed by Synthia-LLC will ultimately be a rapid, field portable device that can be used to provide precise measures of environmental exposure of humans to polybrominated diphenyl ether flame retardants (PBDEs). Precise measurement information can then be used to reduce exposures and thus risk of these toxic compounds.